: : Homo erectus has begun to interest me of late. According to speciation
: : theory, in order for speciation to occur you have to have reproductive
: : isolation at some point. If the multi-regionalists are correct (and I
: : am not saying that they are correct) then there has been no reproductive
: : isolation during the transition from Homo erectus to Homo sapiens. If
: : this is true, then we need to ask if vectored change alone over time is
: : enough to justify changing species. In other words, an argument can
: : be made that Homo erectus should be renamed Homo sapiens.

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: You can have a shift in characteristics via two alternative mechanisms
: to reproductive isolation:

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: 1. A global change in the environment that changes the fitness function
: for the species. In that case, you would see a global change in the
: characteristics of the species, or
: 2. A local environmental change that results in a local race modifying a
: characteristic to the point that a new fitness optimum becomes
: accessible. The characteristic then spreads through the species.
: The issue of whether the later population differs from the earlier
: population in the same way that two simultaneously existing species
: differ cannot be answered. You also have the issue of two local
: populations that do not interbreed, but still sharing genes via
: intermediates...

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Jay Allen Texas-Ex '93 Tulane Medical School
Southeastern Intercollegiate Sailing Association Executive Vice-President
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--- If you're a horse, and someone gets on you, and falls off, and then
--- gets right back on you, I think you should buck him off right away.